This invention relates to a fire damper, which is formed of a tubular mantle intended for installation in a ventilation duct mounted in the through hole of a separating building element in order to limit the spreading of combustion and flue gases from one fire compartment to another via the ventilation duct.

The fire damper plays an essential part in the fire safety of a building. Under the harmonised European standard, fire dampers are assessed as class 1 AVCP for building products.

The fire damper consists of an outer mantle and a closing plate meeting the fire resistance rating of a separating building element (a wall or an intermediate floor), which, in its closed position, limits spreading of heat, fire and/or flue gases via the ventilation duct from one fire compartment to another. The spring-loaded closing plate of an independent (manual) fire damper closes when the fuse of the fire damper detects that the temperature limit value in the ventilation duct is exceeded. The closing plate of a fire damper equipped with an actuator is closed when the heat detector detects that the temperature limit value in the ventilation duct is exceeded. Then the heat detector switches off the tension of the actuator so that the spring in the actuator retracts the closing plate into closed position.

The invention relates to a tubular round fire damper meeting fire resistance class EI60, which is intended for installation in the ventilation duct of a building in a building element separating a fire compartment (a wall or an intermediate floor) in order to prevent spreading of fire and flue gases via the ventilation duct from one fire compartment to another. Fire class EI60 signifies that the fire damper under EN standard 13501-3 meets the sealing and insulation requirements of SFS-EN standard 15650 for a 60 minute duration. In Finland, fire dampers shall meet the fire technical demands of harmonised SFS-EN standard 15650 and they shall be CE marked under the EU

Construction Products Regulation 305/2011. Since an opening is required for the ventilation duct in a separating building element (the through hole for the ventilation duct), a fire damper is installed in a ventilation duct with the purpose to stop heat, fire and flue gases from spreading from one compartment to another in the case of fire.

There is a plurality of commercially available round tubular fire dampers meeting the standard requirements. The tubular mantle has a variable length and the fire damper may comprise a protruding adapter flange of sheet metal or an insulated flange ("Limppu"). In terms of fire safety, it is crucial always to install the fire damper correctly following the mounting instructions, and then the position of the closing plate relative to the separating building element is of great significance. In terms of fire safety, this involves that fire dampers require a significant amount of complementary work. This is usually done by first installing the ventilation duct through the through hole and by cutting it level with the wall surface (the separating building element) on the other side. After this, the fire damper is mounted as an extension of the ventilation duct on the outer side of the wall surface (the separating building element). This arrangement reduces fire safety, and for correct installation, the distance between the closing plate and the wall surface should be fire-insulated or protected in some other manner in accordance with the mounting instructions in order to prevent thermal radiation from spreading from the fire damper mantle to the adjacent fire compartment and from initiating fire in this. Another manner of installing is connecting the tubular fire clamper to the separating building element before installing the ventilation ducts, with the closing plate positioned in the centre of the separating element. In terms of installation techniques, installing/connecting a ventilation duct with a fire damper afterwards is an extremely demanding operation, because it requires correct evaluation, over a long distance, of the length and height relation of the ventilation duct to be installed relative to the fire damper previously connected to the separating building element.

The fire damper of the invention is characterised in that one end of the fire damper mantle has a smaller diameter so that it can enter the ventilation duct, and it has been extended, with the extended part reaching, when mounted, into the separating element of the ventilation duct and the closing plate being located within the extended part and also within the separating element.

Various embodiments of the invention are described in the dependent claims of the set of claims.

Without complementary work, the tubular fire damper of the invention provides easy and cost- effective installation in a ventilation duct, which has been installed in the through hole of a separating building element and with the duct end cut off so as to be level with the visible surface of the separating building element. This is a straightforward manner of installation which does not compromise fire safety, because the closing plate, which stops fire and flue gases from spreading from one fire compartment to another, will be located within the separating building element when the fire damper is installed in the manner described above.

The invention is explained in greater detail below with the aid of an example and with reference to the accompanying drawings, in which

Figure 1 is an axonometric view of the fire damper,

Figure 2 shows the fire damper in section with the closing plate in open position,

Figure 3 shows the same as figure 2, but with the closing plate in closed position and

Figure 4 shows the fire damper installed in a ventilation duct and in the through hole 11 of a building element.

The fire damper consists of the following parts:

A round tubular mantle 1, whose one end 4 has a diameter that has been reduced and extended all the way to the bead 2 so as to enter completely the round ventilation duct 12. The round end 4 of the mantle of the tubular fire damper is inserted into the ventilation duct all the way to the bead 2. The extended mantle part 4 is provided with a closing plate 5, and a heat expanding seal 9 and a duct seal 3 are provided on the outer side of the mantle. An air seal 8 is provided at the outer edge of the closing plate 5. The closing plate 5 is closed by the arm 10 operated by the drive shaft 7, which can be connected either with a manual fuse trigger or an electric actuator supplied on the installation shelf 6. The other end of the round tubular mantle 1 is also equipped with a beading 2 and a duct seal 3, to which the ventilation duct can be connected. When installed, the extended part 4 reaches inside the separating element 13 of the ventilation duct 12 and the closing plate 5 is located within the extended part 4 and also within the separating element 13.